The focus of the proposed research is the distinction between two functions of time in conditioning. The value-conferring function refers to the effect of temporal parameters of reinforcement upon the strength of behavioral control accruing to stimuli associated with reinforcement. For example, stimuli associated with shorter delays to reinforcement exert stronger control over behavior than stimuli associated with longer delays. The second function of time refers to its role as a cue, as exemplified by the phenomenon of Pavlovian temporal conditioning, and by the concepts of "eliciting" and "discriminative" properties of stimuli in Pavlovian and operant procedures, respectively. While the distinction between value and cue functions of stimuli has long been recognized in conditioning theory, little attention has been given to the dissociation of these functions with respect to the role of time. Three experiments are proposed which seek to refine the notion of temporal control of behavior by isolating each of the two functions of time as they operate within a single procedure. Experiment 1 utilizes an autoshaping procedure in which different keylights are associated with different delays to reinforcement on separate trials. Temporal control is assessed by choice behavior on test trials with both cues present. Cue and value functions of time are inferred from differences in choice predicted at different temporal loci within test trials. Experiment 2 uses a stimulus shift procedure in order to isolate control by temporal and nontemporal stimulus elements. Experiment 3 involves a comparison between a conventional two-link concurrent chains choice procedure and a response-independent variant of that procedure. Previous analyses of behavior in the conventional procedure have focused upon the value-conferring function of time. Experiment 3 examines the role of cue functions of temporal and nontemporal stimulus elements in choice behavior in the presence and absence of the value-conferring function of time.